Searching \ for '[PIC]: Comparator with very low reference (16F628)' in subject line. ()
Make payments with PayPal - it's fast, free and secure! Help us get a faster server
FAQ page: www.piclist.com/techref/microchip/devices.htm?key=16F
Search entire site for: 'Comparator with very low reference (16F628)'.

Exact match. Not showing close matches.
PICList Thread
'[PIC]: Comparator with very low reference (16F628)'
2001\09\21@102825 by =?Windows-1252?B?SmVz+nM=?=

flavicon
face
Hi all,

I want to detect the presence of audio signal in a line. I will use 16F628 and I am interested in minimising the external hardware (avoid operational amplifiers)

The typical audio signal is 0.03 V rms.
1.- can I use a Vref (external, cause the minimum internal one is 5/24=0.2 V) as amall as 0.02 V?

2.- And more interesting, Can I use the output of the comparator (pin RA4, mode 010) to feedback the internal operational amplifier with a resistor so that a gain is obtained?

Thank you in advance for your answers!

------------
Jesús Gonzalo
Ingeniería y Servicioc Aeroespaciales, SA.
-------------

--
http://www.piclist.com hint: The PICList is archived three different
ways.  See http://www.piclist.com/#archives for details.



'[PIC]: Comparator with very low reference (16F628)'
2001\10\11@114957 by Roman Black
flavicon
face
=?Windows-1252?B?SmVz+nM=?= wrote:
>
> Hi all,
>
> I want to detect the presence of audio signal in a line. I will use 16F628 and I am interested in minimising the external hardware (avoid operational amplifiers)
>
> The typical audio signal is 0.03 V rms.


Hi, I think if this is for a "proper" product
you will need to look closely at 3 things:

* A very safe "dead zone" or base blanking level.
* Some audio filtering by frequency.
* A time delay on audio input blanking.

These things are typical in most audio detection
equipment. Some of my studio equipment had base
level detection, for voice-over microphone etc,
which had dials for level, time delay, and freq.

If you want this thing to perform well and NOT
record every hum, click and pop you need to think
about these 3 factors and even allow adjustment
so they can be tuned for best performance in each
installation. I think an op-amp and some simple
filtering is going to be very needed to get the
best performance here. :o)
-Roman

--
http://www.piclist.com hint: The PICList is archived three different
ways.  See http://www.piclist.com/#archives for details.


More... (looser matching)
- Last day of these posts
- In 2001 , 2002 only
- Today
- New search...